1868 Ecuador earthquakes

Tectonic setting

The active tectonics of Ecuador is dominated by the effects of the subduction of the Nazca plate beneath the South American plate. The high degree of coupling across the plate boundary where the Carnegie Ridge is being subducted beneath northern Ecuador causes unusually intense intraplate deformation. Known faults within the area of the earthquake epicenters are the SSW-NNE trending San Isidro, El Ángel, Río Ambi and Otavalo Faults, all considered to be dextral strike-slip faults, sometimes with reverse movement. All these faults are interpreted to have moved in the last 1.6 million years.

Damage

15 August

The towns of El Ángel and La Concepcion were severely shaken by the first earthquake and El Ángel was described as "ruined".

16 August

Ibarra was devastated, with every building destroyed and only a few walls left standing. Nearby Otavalo was left without a single house standing and 6,000 people died. In Imbabura Province, there were 15–20,000 casualties.

Characteristics

There was a minor foreshock the previous afternoon (possibly the 15 August event), with the mainshock occurring at 01:30 local time early on the morning of 16 August. The shaking lasted for one minute.

Aftermath

The relief efforts were organised by Gabriel García Moreno, who had been appointed to that role by the federal government.

On 26 April each year, in the 'El Retorno' festival, Ibarra celebrates the return of the inhabitants in 1872 after a four-year absence following the earthquake.

References

References

1. Giesecke, A.. (2004). "The CERESIS earthquake catalogue and database of the Andean Region: background, characteristics and examples of use". Annals of Geophysics.
2. National Geophysical Data Center / World Data Service (NGDC/WDS): NCEI/WDS Global Significant Earthquake Database. NOAA National Centers for Environmental Information. (1972). "Comments for the Significant Earthquake (16 August)". NOAA National Centers for Environmental Information.
3. Gutscher, M.-A.. (1999). "Tectonic segmentation of the North Andean margin: impact of the Carnegie Ridge collision". Earth and Planetary Science Letters.
4. (2003). "Map of Quaternary Faults and Folds of Ecuador and Its Offshore Regions". United States Geological Survey.
5. National Geophysical Data Center / World Data Service (NGDC/WDS): NCEI/WDS Global Significant Earthquake Database. NOAA National Centers for Environmental Information. (1972). "Comments for the Significant Earthquake (15 August)". NOAA National Centers for Environmental Information.
6. Orton, J.. (2008). "The Andes and the Amazon". BiblioBazaar, LLC.
7. Henderson, P.V.N.. (2008). "Gabriel García Moreno and conservative state formation in the Andes". University of Texas Press.
8. (2007). "Footprint Ecuador and Galápagos". Footprint Travel Guides.